Absorbent articles, such as sanitary napkins, diapers, incontinence protectors, panty liners and tampons have consistently been packaged in open packages into which air can enter freely. Packaging of this nature has many advantages. Handling with respect to manufacture and also with respect to the individual consumer is facilitated by the fact that the package containing the absorbent article can be compressed (air can leave the package freely), and the package can also be easily opened. It is also difficult from a purely technical aspect to produce tight joins at present day production rates.
However, it is becoming more common to include different active additives in absorbent products for different reasons. Examples in this respect are odour-inhibiting additives or deodorants, such as zeolites and silica for example, as described, inter alia, in WO 97/46188, WO 97/46190, WO 97146192, WO 97/46193, WO 97/46195 and WO 97/46196. These additives are intended to act essentially in the product. Another example is the addition to diapers of softeners, e.g. lotions, which shall be transferred from the product to the wearer's skin. A further example is the addition of lactobacilli with the intention of inhibiting bacteria in the product, or for transfer to the wearer and thereby enhance defence against undesired bacteria. The addition of lactobacilli and their favourable effects is also mentioned in, inter alia, SE 9703669-3, SE 9502588-8, WO 92/13577, SE 9801951-6 and SE 9804390-4.
The aforesaid additives often loose some of their properties or effectiveness at high moisture contents. This problem is thus new in the field of absorbent products. The odour-inhibiting capacity of zeolites is reduced when they become saturated with water. This is mentioned, inter alia, in WO 98/17239. One problem with lactobacilli in absorbent products resides in their rapid demise when exposed to ambient moisture and temperature above a certain threshold; see FIG. 3. Thus, in normal surroundings such as in transportation and during storage, for instance, the absorbent articles will be subjected to such conditions as to render the death of the lactobacilli present unavoidable (see FIG. 1) when the articles are packaged in accordance with known technology. Survival of lactobacilli can be achieved by bringing them into a rest state. This state can be achieved either by freezing or drying the lactobacilli, or by a combination of these processes, i.e. so called freeze-drying. In order to make possible the use of conventional absorbent product distribution and sales channels, drying of the lactobacilli and retention of this dryness is preferred to freezing. When the product, or article, is applied to the body, the moisture and temperature conditions that then prevail will be optimal for reactivation of the lactic acid bacteria.
However, it may be difficult to retain dryness when storing in a humid atmosphere. This applies particularly to absorbent products, as it lies in the nature of the product to absorb moisture from the surrounding atmosphere. It is therefore particularly important to protect absorbent products that contain lactobacilli against high humidities. The packages used at present for packaging absorbent articles cannot be considered to satisfy the need for such protection, partly because the material used is moisture permeable and secondly because the packaging joins or seams are not tight. Single-item packaging units for sanitary napkins and panty liners are often comprised of polypropylene or polyethylene plastic, which have a relatively high moisture permeability (see table 1, film 8), and the packages are also often provided with an unsealed opening in the centre of the package, so that air is able to pass freely into and out of the package and therewith permit a certain degree of compression. External wrappers or bags are also often perforated to facilitate opening of the package.
U.S. Pat. No. 5,833,070 refers to a stretched film of polychlorotrifluoroethylene, a method for its production, and a product package, in which the film is used. The film must at least partly comprise trifluoroethylene. The film can be used to pack some products in a moisture impermeable way, such as preferably an electro-luminiscent means. Thus, this film is stretched, which leads to it being stiff, fragile and rustle. Accordingly, it is not suitable as a package film for hygiene articles for some reasons. A film for hygiene articles should be silent and smooth to be experienced as discrete by the consumer. A film for hygiene article applications should also be possible to fold, which makes a stiff film unsuitable. Further, the air in the product should be pressed out in the same step as the packaging, which makes a stiff, blister-package like film inadequate.
EP-A1-0773102 refers to a multi-layer laminate and its use. One of the layers must at least partly comprise an ethylene-/cycloolephine-copolymer, and one layer must be a polymer layer. Polyethylene, polypropylene and vinyl are mentioned as possible materials. The thickness of the layers can be 1 μm-10 mm. This laminate can be used as a moisture protection for drugs and food. The laminate is for instance suitable for use as a PTP (press through pack) or as a blister package. Those types of packages are not suitable for absorbent products, for the reasons discussed above.
Further, EP-A2-0613824 discloses a moisture tissue-containing package, having the object to retain the moisture in a package. The film disclosed here is too thick for use in relation to absorbent articles. U.S. Pat. No. 5,443,161 describes a moisture impermeable “baby-care”-kit, in which the package consists of a polypropylene layer, having a thickness of 2 mm.
In summary, there is thus a need to package absorbent articles that contain moisture-sensitive additives in a manner, which will ensure that these additives will not be harmed or destroyed and which will also ensure that the quality of the product is retained.